A single 4PST relay is about the same price, but more compact, than 4 separate "ordinary" SPST ones, or 2 * DPST as an intermediate solution.( http://www.newark.com/panasonic-ew/s4eb-12v/power-relay-4pst-12vdc-4a-pc-board/dp/46F5824 )

i did think of doing it that way but not much choice on 5v, i wanted to make it bomb proof, i intend using a 8a dp contacts doubling up on those giving me 16acheers

If you need to turn on or off four different 230 VAC circuits AT THE SAME TIME but keep them isolated from each other, use solid state relays:

These little modules have optical isolation, take in 3 to 20 volts DC at a few milliamps (TTL levels) and can control 230, 460 and more volts at 25, 50 and more amperes. They are completely isolated, so you can wire one end to an Arduino and the other end directly to a load safely.